This map layer shows point locations of costly individual landslide events
in the 50 United States and Puerto Rico. Landslide locations were
determined from published landslide maps and coordinates, and in several
cases the points locate the nearest town or other geographic feature. In
all cases the locations should be considered approximate. Costly events
are defined as those where there was public or private property damage or
loss of human life. Landslides are defined in a broad manner, to include
most types of gravitational mass movement such as rockfalls, debris flows,
and the failure of engineered soil materials. Landslide causes include
earthquakes, reservoir draw-downs, and heavy precipitation.

Supplemental_Information:

The purpose of this project was to identify and compile data relating to
the most costly landslide events in the United States. Damage estimates
are generally direct costs, or calculable expenses incurred by owners of
private or public property that were impacted by a landslide. Many of the
highest costs were the result of damage to the transportation
infrastructure. For example, the 1983 Thistle Landslide in Utah destroyed
a section of both U.S. Highway 6 and the main line of the Denver and Rio
Grande railway. Much of the estimated cost of $400 million was attributed
to the damage to these transportation routes. Indirect costs such as
those incurred through increased travel times, loss of jobs, and reduced
income as a result of a landslide event can be significant. However, an
accurate accounting of these costs is often difficult. For example, the
April 1998 Anzar Road landslide in San Benito County, California severed a
utility line that provided natural gas service to an adjacent county.
Restaurants and other businesses were forced to close for a time,
resulting in lost revenues, wages, and income for the people affected.

An additional map layer showing costly regional landslide events is also
available as part of the National Atlas of the United States. Regional
events are those where extensive landsliding was triggered by a single
meteorological or seismic event. The regional extents should also be
considered approximate, and in several cases the limits shown represent an
arbitrary administrative boundary rather than the extent of landsliding
related to a storm or earthquake.

Horizontal positions are specified in geographic coordinates, that is, latitude and longitude.
Latitudes are given to the nearest 0.000278.
Longitudes are given to the nearest 0.000278.
Latitude and longitude values are specified in Decimal degrees.

The horizontal datum used is North American Datum of 1983.
The ellipsoid used is GRS1980.
The semi-major axis of the ellipsoid used is 6378137.0.
The flattening of the ellipsoid used is 1/298.257222.

A place where a costly landslide has occurred.
(Source: National Atlas of the United States)

Shape

The representation of the entity in the data.
(Source: National Atlas of the United States)

Value

Definition

Point

0-dimensional element.

Area

The size of the shape in coverage units. In the distributed
file, coverage units represent square decimal degrees.
(Source: National Atlas of the United States)

Range of values

Minimum:

0.000

Maximum:

0.000

Perimeter

The perimeter of the shape in coverage units. In the distributed file,
coverage units represent decimal degrees.
(Source: National Atlas of the United States)

Range of values

Minimum:

0.000

Maximum:

0.000

Landslx020

Internal feature number.
(Source: National Atlas of the United States)

Range of values

Minimum:

1

Maximum:

32

Type

Landslide type.
(Source: U.S. Geological Survey)

Value

Definition

D

Reservoir dam failure

L

Landslide

R

Rockslide/rock avalanche

Year

The year of the landslide occurrence.
(Source: U.S. Geological Survey)

Range of values

Minimum:

1925

Maximum:

1998

Month

The month of the landslide occurrence. A value of 0 indicates either
that the month is unknown, or that the landslide event took place over
more than one month.
(Source: U.S. Geological Survey)

Range of values

Minimum:

0

Maximum:

8

Day

The day of the landslide occurrence. A value of 0 indicates either that
the day is unknown, or that the landslide event took place over more
than one day.
(Source: U.S. Geological Survey)

Range of values

Minimum:

0

Maximum:

22

Locality

The location of the landslide. The locality can be the name of a nearby
town or place, the name of the landslide itself, or the name of a dam.
The locality includes the State or territory name.
(Source: U.S. Geological Survey)

There is no predefined set of valid localities.

Deaths

The number of fatalities associated with the landslide.
(Source: U.S. Geological Survey)

Range of values

Minimum:

0

Maximum:

500

Comments

Significant features of the landslide event.
(Source: U.S. Geological Survey)

There is no predefined set of valid comments.

Trigproc

The process that triggered the landslide, such as rainfall or an
earthquake. A blank indicates the trigger is unknown.
(Source: U.S. Geological Survey)

There is no predefined set of valid landslide triggers.

Name

The name of the landslide.
(Source: U.S. Geological Survey)

There is no predefined set of valid landslide names.

Damage___m

The cost of damage attributed to the landslide, in millions of U.S.
dollars. A value of 0 indicates that the damage costs are not known.
(Source: U.S. Geological Survey)

Range of values

Minimum:

0.0000

Maximum:

900.0000

Reference

The bibliographic reference(s) from which the information on the
landslide was drawn.
(Source: U.S. Geological Survey)

Formal codeset

Codeset Name:

Landslides Bibliography

Codeset Source:

The full bibliography is available from the Point of Contact listed above, and is also included as a text file bundled with the downloadable data.

Number

Internal reference number for the landslide.
(Source: U.S. Geological Survey)

Range of values

Minimum:

1

Maximum:

32

State

The 2-letter code for the State in which the facility is located.
(Source: U.S. Geological Survey)

Formal codeset

Codeset Name:

Codes for the Identification of the States, the District of Columbia and the Outlying Areas of the United States, and Associated Areas, FIPS 5-2, 1987.

Codeset Source:

U.S. Department of Commerce, National Institute of Standards and Technology

State_fips

The two-digit code for the State in which the facility is located.
(Source: U.S. Geological Survey)

Formal codeset

Codeset Name:

Codes for the Identification of the States, the District of Columbia and the Outlying Areas of the United States, and Associated Areas, FIPS 5-2, 1987.

Codeset Source:

U.S. Department of Commerce, National Institute of Standards and Technology

These data are intended for geographic display and analysis at the
national level, and for large regional areas. The data should be
displayed and analyzed at scales appropriate for 1:2,000,000-scale data.
No responsibility is assumed by the National Atlas of the United States or
the U.S. Geological Survey in the use of these data.

Although these data have been processed successfully on a computer system at
the U.S. Geological Survey, no warranty expressed or implied is made by the
U.S. Geological Survey regarding the utility of the data on any other
system, nor shall the act of distribution constitute any such warranty. No
responsibility is assumed by the U.S. Geological Survey in the use of these
data.